Explore chapters and articles related to this topic
Introduction to basic immunology and vaccine design
Published in Amine Kamen, Laura Cervera, Bioprocessing of Viral Vaccines, 2023
Alaka Mullick, Shantoshini Dash
The other important type of T-cells are the cytotoxic T-cells. This type of T-cell attacks abnormal cells, such as those infected by a virus. Intracellular proteolytic fragments of a pathogen or abnormal protein are displayed on the surface of the cell in question, and are recognized by T-cells expressing receptors that specifically recognize those fragments. As shown in Figure 3.12, upon activation by antigen-binding, cytotoxic T-cells produce perforin, a molecule that will kill the cell by making holes in it. They also produce granzymes, molecules that trigger apoptosis in the target cell. Cytotoxic T-cells induce cell death very much like NK cells, but their action is much more specific because T-cells recognize their targets with the help of very specific receptors. Figure 3.13 shows the difference in function of the two types of T-cells, one that supports antibody formation in B cells (T-helper) and the other that triggers cell death (killer T) in abnormal cells such as those that are virally infected or cancerous [7].
Current and Rising Concepts in Immunotherapy: Biopharmaceuti cals versus Nanomedicines
Published in Raj Bawa, János Szebeni, Thomas J. Webster, Gerald F. Audette, Immune Aspects of Biopharmaceuticals and Nanomedicines, 2019
Cytotoxic T cells can actively kill cancer cells, but during autoimmune disease, they destroy the body’s-own cells. In the course of therapies, they can be depleted using anti-CD8 antibodies [64]. In order to use their killing capabilities to fight cancer, innovative strategies already make use of cytotoxic CD8 cells. Many fields of research have been inspired a lot by the inhibitors of programmed cell death 1 (PD1), such as pembrolizumab. In this regard, immunomodulatory therapies utilize the killing capabilities of T cells for killing tumor cells [65]. The so-called chimeric antigen receptor (CAR)-T cells represent another major innovation which has been approved in 2017 by the FDA for children and young adults with relapsed or refractory B-cell acute lymphoblastic leukemia [66]. CAR T cells are generated based on extracting a patient’s immune cells and genetically engineering and reinjecting them into the patient where they shall seek and destroy cancer cells [67].
Bioartificial organs
Published in Ronald L. Fournier, Basic Transport Phenomena in Biomedical Engineering, 2017
Figure 11.4 illustrates how the CD8+ T cell becomes activated. Here, we see that the CD8+ TcR binds with the antigen/MHC class I complex presented, e.g., by a virally infected cell. Once again, the CD8 molecule stabilizes the interaction between the TcR and the antigen/MHC complex. This binding of TcR and antigen/MHC complex represents the first signal. In order for the CD8+ T cells to proliferate, i.e., form a clone of CD8+ T cells and become activated, it also must receive a second signal that is provided by the IL-2 that is released as a result of the activation of the CD4+ T cell shown in Figure 11.3. The activated CD8+ T cell will then kill any cell that expresses the appropriate combination of antigen and MHC class I. The activated CD8+ T cell accomplishes this cellular destruction through the release of special molecules called perforins that destroy the cell membranes of the target cell. Because of their role in cell death, the CD8+ T cells are also known as cytotoxic T cells or killer T cells.
Effects of life-stage and passive tobacco smoke exposure on pulmonary innate immunity and influenza infection in mice
Published in Journal of Toxicology and Environmental Health, Part A, 2022
Lei Wang, Maya Rajavel, Ching-Wen Wu, Chuanzhen Zhang, Morgan Poindexter, Ciara Fulgar, Tiffany Mar, Jasmine Singh, Jaspreet K. Dhillon, Jingjing Zhang, Yinyu Yuan, Radek Abarca, Wei Li, Kent E. Pinkerton
Infiltration of immune cells in bronchoalveolar lavage fluid (BALF), inflammation of lung tissue (histopathology), distribution of CD4-, CD8-, and CD25-positive T cell markers in lung tissue, and expression of interferon mRNA (IFN) in spleen tissue were determined following IAV inoculation. T cells are the most important lymphocyte trafficking to the lungs during the first week of viral infection. The CD4, CD8, and CD25 T cell markers were selected to visualize populations of helper, cytotoxic, and regulatory T cells, respectively. CD4-positive, helper, T cells interact with antigen-presenting cells (e.g., macrophages) to shape pathogen-specific, adaptive immune responses, such as antibody production and cytotoxic T cell activation (Figure 1; Sant et al. 2018a; Sant, Richards, and Nayak 2018b; Lee and Lawrence 2018). CD8-positive, cytotoxic, T cells induce death of pathogen-infected, damaged, or dysfunctional cells (Pizzolla et al. 2017; Smed-Sörensen et al. 2012). CD25-positive, regulatory T cells are a subset of CD4-positive cells which suppress the activities of other T cells, B cells, and antigen-presenting cells (Corthay 2009). These three cell types are important factors in the immune response to viral infections (Rosendahl Huber et al. 2014).
A mathematical model of cytotoxic and helper T cell interactions in a tumour microenvironment
Published in Letters in Biomathematics, 2018
Heidi Dritschel, Sarah L. Waters, Andreas Roller, Helen M. Byrne
There are two populations of T cells, helper and cytotoxic, which are distinguished by their expression of CD4 and CD8 proteins, respectively. Naive helper T cells are activated by antigen presented with a major histocompatibility complex (MHC) class II molecule. (A glossary of the terminology used in this article is provided in Appendix 1.) Naive cytotoxic T cells are activated by antigen presented with an MHC class I molecule. Once activated the helper and cytotoxic T cells perform complementary functions to eliminate the tumour. Helper T cells further differentiate into subpopulations classified by the specific cytokines that they produce. In this way, they regulate multiple aspects of an immune response. For example, they promote the proliferation of cytotoxic T cells, they recruit and promote cells of the innate immune response, and they control levels of inflammation at the tumour site (Hung et al., 1998; Magombedze et al., 2013). (In this work, we do not distinguish these subpopulations.) Cytotoxic T cells scan the body for transformed cells (cancer cells) to which they bind before inducing cell killing.